Elevated titers of anti-GM1 ganglioside antibodies (anti-GM1) are associated with multifocal motor neuropathy, lower motor neuron disease syndromes, and with the acute motor axonal neuropathy variant of the Guillian-Barrxc3xa9 syndrome.1-5 Assays for anti-GM1 antibodies are routinely used in clinical practice to aid in the evaluation of patients suspected of having these syndromes.
Anti-GM1 antibodies are typically measured using the ELISA system, in which increasing serum dilutions are tested for binding to GM1-coated microwells.6 However, the assay takes several days to perform, is costly, and is done at non-physiologic conditions of temperature and antibody concentration. Issues of methodology have also limited the usefulness of the technique.7-10 There is a need for a faster and more reliable test to detect and measure anti-GM1 antibodies.
Here we disclose a novel method for the rapid detection and quantitation of serum antibodies in serum. In the invention disclosed here we present data showing quantitation of serum anti-ganglioside antibodies in serum. The system utilizes a surface plasmon resonance-based optical biosensor. Gangliosides are immobilized on the surface of a sensor chip comprised of a carboxymethyl dextran layer linked to a thin gold film coated on a glass slide. The sensor chip is brought in contact with a flow cell carrying the analyte. Applying the phenomenon of surface plasmon resonance, possible interactions between the analyte in the flow cell and the gangliosides, leading to changes in the refractive index at the surface of the chip, can be followed.11,12 The binding of anti-GM1 antibodies in a sample to immobilized GM1 can be observed in real time without the use of secondary labels. The invention disclosed here reveals a method of diagnosing human diseases by detection and quantitation of antibodies in human sera.
The present invention provides a method of detecting antibodies in a solution comprising:
a) contacting the solution with an antigen-coated surface of a sensor chip under conditions that permit anti-antigen antibodies to bind to the antigen coating;
b) detecting the change in surface plasmon resonance signal of the sensor chip resulting from the anti-antigen antibodies binding to the antigen coating.
The present invention provides a method of detecting antibodies as described hereinabove, wherein the antigen is a glycolipid.
The present invention provides a method of detecting antibodies as described hereinabove wherein the anti-antigen antibodies are anti-glycolipid antibodies.
The present invention provides a method of detecting antibodies as described hereinabove wherein the antigen is a ganglioside and the anti-antigen antibodies are anti-ganglioside antibodies.
The present invention provides a method of detecting anti-glycolipid antibodies in a solution wherein the solution contains anti-glycolipid antibodies that bind to the glycolipid-coated surface of the sensor chip and alter the surface plasmon resonance.
The present invention provides a method of detecting anti-glycolipid antibodies in a solution as described hereinabove, wherein the glycolipid is a ganglioside and wherein a control surface plasmon resonance value is subtracted from the surface plasmon resonance signal.
The present invention provides a method of detecting anti-glycolipid antibodies in a solution as described hereinabove, wherein the control surface plasmon resonance value comprises the signal detected from the surface of the sensor chip coated with a control antigen, wherein the chip is also alternatively exposed to the solution being evaluated for anti-glycolipid antibodies. The present invention also provides a method wherein the control antigen is ganglioside GM2. The present invention also provides a method wherein the anti-antigen antibody is anti-ganglioside GM1 antibody.
The present invention provides a method of detecting anti-glycolipid antibodies in a solution as described hereinabove, wherein the surface plasmon resonance signal is detected using an optical detector.
The present invention provides a method of detecting anti-glycolipid antibodies in a solution as described hereinabove, wherein the solution is human blood or a derivative of human blood.
The present invention provides a method of detecting anti-glycolipid antibodies in a solution as described hereinabove, wherein the solution is human sera.
The present invention provides a method of detecting anti-glycolipid antibodies in a solution as described hereinabove, wherein the anti-glycolipid antibody is an anti-glycolipid Immunoglobulin G.
The present invention provides a method of detecting anti-glycolipid antibodies in a solution as described hereinabove, wherein the anti-glycolipid antibody is an anti-glycolipid Immunoglobulin M.
The present invention provides a method of detecting anti-glycolipid antibodies in a solution as described hereinabove, wherein the anti-glycolipid antibody is an anti-ganglioside antibody.
The present invention provides a method of detecting anti-glycolipid antibodies in a solution as described hereinabove, wherein the anti-glycolipid antibody is human.
The present invention provides a method of determining the anti-glycolipid antibody isotype present in the solution comprising the methods described hereinabove, wherein the tested solution is washed from the surface of the sensor chip and a second solution containing a secondary antibody is introduced to the surface.
The present invention provides a method of increasing the optical signal size of the methods described hereinabove, comprising washing the tested solution from the surface of the sensor chip and applying the second solution containing the secondary antibody to the surface.
The present invention provides a method of detecting anti-glycolipid antibodies in a solution as described hereinabove, wherein the secondary antibody is an anti-Immunoglobulin G.
The present invention provides a method of detecting anti-glycolipid antibodies in a solution as described hereinabove, wherein the secondary antibody is an anti-Immunoglobulin M.
The present invention provides the use of the methods described hereinabove in diagnosing a disease in a subject.
The present invention provides the use of the methods described hereinabove in diagnosing a neurological disease in a subject.
The present invention provides the use of the methods described hereinabove in quantitating levels of anti-antigen antibodies in a subject.
The present invention provides the use of the method described hereinabove in evaluating a neuropathic disease in a subject, wherein the disease is Guillian-Barrxc3xa9 syndrome, motor neuropathy, peripheral neuropathy or autoimmune neuropathy.